A mobile elevating work platform conventionally consists of a base that is wheeled and may be either self-propelled or towable, an extending structure (for example a boom or other lifting structure) mounted on the base that may be articulated and/or telescopic, and an operator cage that is attached to the end of the extending structure. The operator cage provides the operator with an enclosed and protected area in which to stand while operating the MEWP. The cage also provides the operator with a platform from which to work when the cage is elevated.
Normally, the cage is a welded steel structure, consisting of base and a fence assembly of posts and rails that is welded to the base. There are a number of disadvantages associated with this type of cage. First, conventional steel cages tend to be heavy and influence the stability of the platform when raised. This affects the safe operating conditions of the platform. Further, operator cages are prone to receiving scrapes, knocks and other damage during use and transportation, and they suffer from corrosion. Cages therefore often have to be repaired or replaced altogether. However, conventional steel cages are difficult to repair and expensive to ship and replace.
Another problem with some MEWPs is that the gate through which an operator gains access to the operator cage is poorly designed. In many MEWPs, a gateway is provided in the fence assembly by omitting a section of a lower guard rail and replacing it with a sliding bar that is connected to the fence posts on either side and can be raised to gain access to the cage then dropped back into position to complete the loop of the lower guard rail. However, using this type of gateway is awkward and inconvenient, as the operator has to lift the sliding bar with one hand while ducking underneath that bar and climbing onto the platform. Consequently, it has been known for operators to fix the sliding bar in the raised position, contrary to safety requirements, thereby negating its effect and creating a safety hazard by increasing the risk that the operator might fall out of the cage.
Another safety hazard can occur if the MEWP is driven backwards with the platform raised, as the operator may not notice an overhead obstruction and may then collide with the obstruction and be crushed against the control console.
Similar risks may also arise in other machines, for example telehandlers and forklifts, in which an operator cage is fitted as an attachment to the load-bearing forks.
It is an object of the present invention to provide an operator cage that mitigates at least some of the aforesaid disadvantages.